Geophysical surveys are often used for oil and gas exploration in geophysical formations, which may be located below marine environments. Various types of signal sources and geophysical sensors may be used in different types of geophysical surveys. Electromagnetic (EM) surveys, for example, may be conducted using EM signals transmitted by an EM source and detected by EM sensors. Seismic geophysical surveys, for example, are based on the use of acoustic waves. In seismic surveys, a survey vessel may tow an acoustic source (e.g., an air gun or a marine vibrator) and a plurality of streamers along which a number of acoustic sensors (e.g., hydrophones and/or geophones) are located. Acoustic waves generated by the source may then be transmitted to the earth's crust and then reflected back and captured at the geophysical sensors. Data collected during a marine geophysical survey may be analyzed to locate hydrocarbon-bearing geological structures, and thus determine where deposits of oil and natural gas may be located.
A typical goal in geophysical marine surveys is to balance adequate regularity in spacing of signal sources and geophysical sensors with reasonable acquisition cost. Often, it is difficult for a navigator to determine the extent to which a current sail line is contributing to coverage during a marine survey. A given sail line should generally avoid unnecessary overlap with previous sail lines, but should not be so far away from previous sail lines as to create coverage holes.
This specification includes references to “one embodiment” or “an embodiment.” The appearances of the phrases “in one embodiment” or “in an embodiment” do not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.
Various units, circuits, or other components may be described or claimed as “configured to” perform a task or tasks. In such contexts, “configured to” is used to connote structure by indicating that the units/circuits/components include structure (e.g., circuitry) that performs the task or tasks during operation. As such, the unit/circuit/component can be said to be configured to perform the task even when the specified unit/circuit/component is not currently operational (e.g., is not on). The units/circuits/components used with the “configured to” language include hardware—for example, circuits, memory storing program instructions executable to implement the operation, etc. Reciting that a unit/circuit/component is “configured to” perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112(f) for that unit/circuit/component.